leds: trigger: netdev: fix handling on interface rename

The NETDEV_CHANGENAME code is not "unneeded" like it is stated in commit
4cb6560514fa ("leds: trigger: netdev: fix refcnt leak on interface
rename").

The event was accidentally misinterpreted equivalent to
NETDEV_UNREGISTER, but should be equivalent to NETDEV_REGISTER.

This was the case in the original code from the openwrt project.

Otherwise, you are unable to set netdev led triggers for (non-existent)
netdevices, which has to be renamed. This is the case, for example, for
ppp interfaces in openwrt.

Fixes: 06f502f57d0d ("leds: trigger: Introduce a NETDEV trigger")
Fixes: 4cb6560514fa ("leds: trigger: netdev: fix refcnt leak on interface rename")
Signed-off-by: Martin Schiller <[e-mail]>
Signed-off-by: Pavel Machek <[e-mail]>

drivers/leds/trigger/ledtrig-netdev.c

···
 		container_of(nb, struct led_netdev_data, notifier);
 
 	if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
-	    && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER)
+	    && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER
+	    && evt != NETDEV_CHANGENAME)
 		return NOTIFY_DONE;
 
 	if (!(dev == trigger_data->net_dev ||
+	      (evt == NETDEV_CHANGENAME && !strcmp(dev->name, trigger_data->device_name)) ||
 	      (evt == NETDEV_REGISTER && !strcmp(dev->name, trigger_data->device_name))))
 		return NOTIFY_DONE;
 
···
 
 	clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
 	switch (evt) {
+	case NETDEV_CHANGENAME:
 	case NETDEV_REGISTER:
 		if (trigger_data->net_dev)
 			dev_put(trigger_data->net_dev);